[Yaesu] Problem aligning the shift/width on the IF unit of an FT-ONE

[David Kirkby]

Hi,
I've got an FT-ONE (S/N 080046, which appears to be one of the later ones).

I've had reports the TX and RX frequencies differ, so I decided to
align it. One does not have to search the web hard to find that the
FT-ONE's tend to go out of alignment a lot.

Not one of the PLL oscillators (20.000 MHz +/- 100 Hz, 48.615 MHz +/-
500 Hz and 54.280 MHz +/- 100 Hz) were correct - all were outside the
specification. But it was easy to bring them back on - how long they
stay correct is another matter.

But aligning the IF unit was more problematic. The first thing
mentioned in the technical manual is to adjust the Width and Shift. It
says to put the rig in USB, put the width and shift controls in the
centre, and adjust TC9001 for 19.7475 MHz on a counter. The problem is
there is no TC9001. Looking in the technical manual I see there were
two versions of the IF unit. It looks like mine is the later one. They
differ in that the one I have has a variable resistor to set the
frequency, not the variable capacitor mentioned in the alignment
section.

There are two problems.

1) The alignment section does not say how to align the version with a resistor.
2) Assuming one is supposed to set the resistor such that the
frequency is the same as on the earlier IF boards, then I can't do
this. No matter where I put that trimmer, I can't get the oscillator
to oscillate at 19.7475 MHz. The closest I can get is about 350 Hz
below that, which is outside the specification, as its supposed to be
set to +/- 100 Hz.

I'm wondering if the frequency this should be set to on the newer IF
boards is not 19.7475 MHz. Or perhaps my crystal has aged too much,
and it can't be put on frequency.

I've not looked at the circuit in any detail, but I assume the new IF
board uses a varicap diode to do the adjustment.

I expect I could get this to oscillate at 19.7475 MHz by changing a
resistor, capacitor, varicap or as a last resort the crystal. But I'm
unsure if that's needed, since the only alignment instructions I have
are for the older IF board.

I note one of the reviews on eham by N8NN on Oct 6, 2006 11:06  says:

"Within the first three months of ownership Yaesu recalled my FT-ONE
to correct the IF Shift/Width function that was not properly aligned
at the factory."

I don't know if "not aligned at the factory" was really a case of
Yaesu realizing it would not stay aligned.

Is there any known mod which will bring this oscillator onto
frequency? Or should the new IF board be aligned differently (that
seems unlikely I must admit).

Dave, G8WRB